Depth of Field in photomicrography

chalcotrichite

 Do you recognize this sample from a previous blog?  What is the more or less vertical line through the left side of the frame?

It is the only part of the frame which is in focus.  How do you do that?  You can't set you depth of field that shallow.  This is a shot from a stack of images.  The stack captures multiple shots each one close to the vertical line in the one above.  It continues until the entire frame has been captured with each part of it in focus.  Special software takes all of the captures and uses just the in focus parts to make an entire image that is in focus.

chalcotrichite

Some of the major software used for this is Helicon Focus and Zerene Stacker.  There are others also.  I'm told that Photoshop does this now but I haven't tried it.

See if you can see the "ridge" in the totally in foxus image above.

I made the capture of this stack with a Pentax 200mm having a Nikon 10x objective mounted at the front.  The field of view, horizontally, is 2.25mm.

Camera Setup

This is how the 10x is mounted on the front of the lens.  This is a different objective but I think you get the idea.